Compensating loop taker mechanisms



Nov. 25, 1969 a. DELLA TORRE 3,

COMPENSATING LOOP TAKER MECHANISMS Filed June 26, 1967 4 Sheets-Shet 1 E INVENTOR. E-L

. Giancar/o Del/a Torre Witness I BY M MM 1 ATTORNEY Nov. 25, 1969 DELLA TORRE 3,479,978

COMPENSATING LOOP TAKER MECHANISMS Filed June 26, 1967 4 Sheets-Sheet 2 Fig.2.

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Nov. 25, 1969 a. DELLA TORRE COMPENSATING LOOP TAKER MECHANISMS 4 Sheets-Sheet 4 INVENTOR. Gianca r/o Del/a Torre Filed June 26, 1967 Witness 1 Www ZTORNEY United States Patent O 3,479,978 COMPENSATING LOOP TAKER MECHANISMS Giancarlo Della Torre, Bressano, Italy, assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Filed June 26, 1967, Ser. No. 648,831 Int. Cl. Db 3/02 US. Cl. 112159 8 Claims ABSTRACT OF THE DISCLOSURE A crankpin is pivotally connected to a crank on a shaft for transmitting motion from the shaft to a loop taker which is pivotally mounted in the frame for lateral oscillation. The pivoted crankpin transmits motion to the loop taker from the shaft while permitting lateral oscillation of the loop taker.

BACKGROUND OF THE INVENTION Field of the invention The invention relates to shifting looper zigzag mechanisms.

Description of the prior art In order to form stitches, there must be cooperation between a needle and a loop taker. The loop taker must be able to seize a loop of thread from the needle. In order to seize the loop of thread, close dimensional tolerances must be maintained between the needle and the loop taker. In sewing machines having needles which oscillate laterally to form zigzag and pattern stitches, if a horizontal axis loozp taker is used, in order to maintain the close dimensional tolerances required between the needle and the loop taker, the loop taker must also oscillate laterally. In general, there are two ways to impart lateral oscillation to a horizontal axis loop taker, both of which have inherent advantages and disadvantages. The loop taker can be reciprocated axially or pivotally oscillated. If the loop taker is pivotally oscillated, a problem arises as to how to connect the loop taker to a shaft so that the shaft can impart motion to the loop taker while permitting lateral oscillation of the loop taker.

SUMMARY OF THE INVENTION It is therefore a primary object of the invention to provide an improved means for connecting a shaft to a pivotally mounted loop taker so that the shaft can impart motion to the loop taker while permitting lateral oscillation of the loop taker.

Another object of the invention is to provide a means in accordance with the foregoing object in which a positive connection is maintained between the loop taker and the shaft at all times, efficient motion is imparted to the loop taker by the shaft, and binding and locking of the parts are eliminated.

Other objects and a fuller understanding of the invention may be had by referring to the description and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal cross sectional view of a sewing machine embodying the invention,

FIG. 2 is a cross sectional View taken substantially along the line 2-2 in FIG. 1,

FIG. 3 is a bottom plan view of the sewing machine shown in FIG. 1,

FIG. 4 is a head end view of the bed of the sewing machine shown in FIG. l,- and 3,479,978 Patented Nov. 25, 1969 ice FIG. 5 is a cross sectional view taken substantially along the line 55 in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawings, the invention is illustrated incorporated in a sewing machine having a frame including a bed 21, a hollow standard 22 rising from one end of the bed, a hollow bracket arm 23 at the top of the standard overhanging the bed, and a sewing head 24 at the free end of the bracket varm.

.Mounted in the sewing head is a needle drive mechanism indicated generally at 25. The needle drive mechanism includes a needle bar gate 26 pivotally mounted on a vertical hinge pin 27 in the sewing head. A needle bar 28 is mounted on the needle bar gate, and a needle 29 is connected to the end of the needle bar.

Endwise reciprocation is imparted to the needle bar by a crank 30 on the end of an arm shaft 31 journaled in a bearing 32 and a bore 33 in the bracket arm. A link 34 is pivotally connected to a crankpin 35 on the crank and to a lateral pin 36 on a clamp 37 on the needle bar to connect the crank to the needle bar. Rotating motion is imparted to the arm shaft through a handwheel 38 on the standard end of the arm shaft.

As is well known in the art lateral oscillation longi tudinally of the bracket arm 23 is imparted to the needle bar gate 26 by a needle jogging mechanism indicated generally at 39. The needle jogging mechanism is connected by a link 40 to a rock arm 41 at the top of a vertical rock shaft 42 journaled in two bores 43 and 44 in the standard. The rock arm in turn is connected to the needle bar gate by a connecting rod 45. At the rock arm, the connecting rod is held in a bore 46 in a pivoted post 47 by a setscrew 48 to provide a lateral adjustment feature for the needle bar gate.

Mounted in the bed is a compensating loop taker mechanism indicated generally at 49. The compensating loop taker mechanism includes a housing 50 which is pivotally mounted on a vertical hinge pin 51 in the bed for pivotal movement about the same side of the hinge pin as the pivotal movement of the needle bar gate 26 about the hinge pin 27 in the sewing head. The housing 50 has a raceway 52, and one end of the naceway is closed by a shuttle cap 53. The shuttle cap is pivotally connected to the housing by a vertical hinge pin 54 and held in closed position by a latch 55 pivotally mounted on the housing by a pivot screw 56. Journaled in the raceway is a shuttle driver 57 and a shuttle 58, and mounted in the shuttle is a bobbin case 59.

Lateral oscillation is imparted to the compensating loop taker mechanism by a connecting rod 60 in the bed. The connecting rod is connected to the housing 50 of the compensating loop taker mechanism by a pivot screw 61 and to a rock arm 62 at the bottom of the vertical rock shaft 42 in the standard by a pivot screw 63. The pivoted post 47 on the rock arm 41 at the top of the vertical rock shaft, in addition to providing a lateral adjustment feature for the needle bar gate 26 as mentioned previously, simultaneously provides a lateral adjustment feature for the compensating loop taker mechanism.

Oscillating motion is imparted to the shuttle 58 by a bed shaft 64 journaled in a bearing 65 and a bore 66 in the bed. Oscillating motion is imparted to the bed shaft by a pitman 67 in the standard. The pitman is connected to a crankpin 68 on the arm shaft and to a rock arm 69 on a short rock shaft 70 held between two pivot screws 71 in the bed. A second rock arm 72 on the short rock shaft is pivotally connected to a crank 73 on the standard end of the bed shaft.

Connected to the other end of the bed shaft by a pin 74 is a second crank 75, and pivotally mounted on the second crank is a crankpin 76 having a shank 77, a finger 78 projecting from the shank, and a spherical surface 79 at the free end of the finger. The crankpin is pivotally held between a pair of lateral lugs 80 on the crank by a hinge pin 81 which extends through a hole 82 in the shank of the crankpin. The axis of the hinge pin is substantially perpendiular to the axis of the bed shaft. The spherical surface 79 at the free end of the finger slidingly seats in a hole 83 in the shuttle driver 57 to transmit the motion of the crankpin to the loop taker.

A coil spring 84 in a recess 85 in the crank 75 bears against the shank of the crankpin offset from the axis of the hinge pin 81 to bias the free end of the finger away from the axis of the bed shaft. A clearance space 86 is provided between a side 87 of the shank of the crankpin and a floor 88 between the two lateral lugs 80 on the crank to permit pivotal movement of the crankpin about the hinge pin. The floor 88 between the two lateral lugs on the crank also provides a stop means for limiting the extent of the pivotal movement of the finger away from the axis of the bed shaft when an edge 89 of the side 87 of the shank contacts the floor.

In operation, the compensating loop taker mechanism 49 and the needle bar gate 26 pivot about the same side of the vertical hinge pins 51 and 27, respectively, in timed relation to provide for extremely uniform cooperation between the shuttle 58 and the needle in both leftmost and rightmost positions. The pivoted crankpin 76 maintains positive contact with the shuttle driver 57 at all times to transmit oscillation to the shuttle from the bed shaft 64 without binding caused by simultaneous lateral oscillation of the compensating loop taker mechanism. The hole 83 in the shuttle driver sliding on the spherical surface 79 of the finger 78 of the crankpin and the pivotal movement of the crankpin prevent binding which permits efiicient motion to be transmitted to the shuttle driver from the bed shaft by the pivoted crankpin. The pivotal movement of crankpin 76 about hinge pin 81 allows the hole 83 to always slide in an axial direction relative to the crankpin and thus binding is prevented.

Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.

Having thus set forth the nature of the invention, what is claimed is:

1. In a zig-zag sewing machine having a frame including a bed, a standard rising from one end of the bed, a bracket arm at the top of the standard overhanging the bed and terminating in a sewing head, a needle bar for a needle mounted in the head, means for imparting endwise reciprocation to the needle bar, means for imparting lateral oscillation to the needle bar in a longitudinal direction relative to the bracket arm, a loop taker, pivot means for mounting the loop taker in the bed for cooperation with the needle and for lateral oscillation, a compensating loop taker mechanism comprising a shaft, means for journaling the shaft in the frame with one end in proximity to the loop taker, means for imparting circular motion to the shaft in timed relation to the endwise reciprocation of the needle, a crank mounted on said end of the shaft to partake of said circular motion, a crankpin connected at one end to the crank, motion receiving means on the loop taker, means on the other end of the crankpin slidingly retained in driving engagement with said receiving means for transmitting said circular motion from the crank to the loop taker, means for moving said loop taker about said pivot means to impart lateral oscillation to the loop taker in timed relation with the lateral oscillation of the needle, and means connecting said crankpin to said crank for allowing sliding of said receiving means along said means on the crankpin in an axial direction relative to the crankpin.

2. The compensating loop taker mechanism of claim 1 in which the motion receiving means on the loop taker is a hole in the loop taker, the means connecting the crankpin to the crank is a hinge pin, and the axis of said hinge pin is substantially perpendicular to the axis of said crank- P111.

3. The compensating loop taker mechanism of claim 2 in which the crankpin includes a shank having a hole for the hinge pin, a finger projecting from the shank, and the means on said other end of the crankpin is a spherical surface at the free end of the finger seating in said hole in the loop taker.

4. The compensating loop taker mechanism as defined in claim 1 wherein the circular motion imparted to the shaft is oscillating motion.

5. The compensating loop taker mechanism as defined in claim 3 wherein the circular motion imparted to the shaft is oscillating motion.

6. In a compensating loop taker zig-zag sewing machine having a frame, a needle bar for a needle mounted in the frame, means for imparting endwise reciprocation to the needle bar, means for imparting lateral oscillation to the needle bar, a loop taker, pivot means for mounting the loop taker in the frame for cooperation with the needle and for lateral oscillation, means for imparting lateral oscillation to the loop taker in timed relation with lateral oscillation of the needle, a loop taker drive comprising a shaft, means for journaling the shaft in the frame with one end in proximity to the loop taker, a crank mounted on said end of the shaft, means for imparting motion to the shaft, means defining a hole in the loop taker, a crankpin including a shank, a hinge pin for pivotally connecting the shank to the crank, a finger projecting from the shank, a spherical surface at the other end of the finger slidingly retained in said loop taker hole for transmitting motion from the shaft to the loop taker, means for biasing said spherical surface end of the finger away from the axis of the shaft and means for limiting the extent of pivotal movement of the finger away from the axis of the shaft.

7. In a sewing machine having a frame, a needle bar for a needle mounted in the frame, means for imparting endwise reciprocation to the needle bar, means for imparting lateral oscillation to the needle bar, a loop taker including a housing having a raceway, a shuttle driver journaled in the raceway, a shuttle driven by the shuttle driver in cooperating relationship with the needle to form zigzag stitches, pivot means for mounting the housing in the frame, means to pivot the housing about the pivot means for imparting lateral oscillation to the shuttle driver in timed relation with the lateral oscillation of the needle, a shaft, means journaling the shaft in the frame with one end in proximity to the loop taker, a crank mounted on said end of the shaft, means for imparting motion to the shaft in timed relation to the endwise reciprocation of the needle, the improvement comprising means defining a hole in the shuttle driver, a crankpin pivotally connected at one end to the crank, means on the other end of the crankpin slidingly received within said hole and retained therein during lateral oscillation of the shuttle driver for imparting to said shuttle driver the motion of the shaft.

8. In a sewing machine as defined in claim 7 wherein the motion imparted to the shaft is oscillating motion and the shuttle driver oscillates the shuttle in cooperating relationship with the needle.

References Cited UNITED STATES PATENTS 2,045,340 6/1936 Bolter 112-159 3,301,207 1/1967 Reeber et al 112-159 X RICHARD J. SCANLAN, 111., Primary Examiner 

